1. Field of the Invention
The present invention pertains to a method for removing overburden material or performing similar earth excavation using blast casting of the overburden material and further removal with an excavator such as a dragline, both in such a way as to reduce the excavating effort to expose a coal or other mineral seam, for example.
2. Background
In large-scale surface mining of coal and other minerals, the removal of overburden earth material is usually the most time-consuming and costly part of the mining process. Other earth excavation operations for construction purposes also, in many instances, consume a major portion of the capital employed in the overall effort. In surface mining, for example, the volume of material mined and the competitive pricing of many minerals, such as coal, is of such magnitude that savings in excavating time and wear and tear on excavating equipment more than offsets any costs due to the requirements to drill blast holes and then blast cast at least a portion of the overburden material in the excavating effort. In this regard the present invention has been developed with a view to utilizing blast casting techniques together with a unique overburden removal process utilizing an excavating apparatus such as a dragline or the like. Another improved method for excavating material in surface mining operations is described and claimed in a patent application entitled "Method for Surface Mining with Dragline and Blast Casting", filed of even date herewith in the name of Steven M. Svatek and assigned to the assignee of the present invention.